TLR4 and pneumocystosis: NF-κB is a classical inflammatory pathway; to investigate the mechanism of action of NAR to inhibit inflammation for the treatment of PCP, we further examined the critical proteins in the NF-κB signalling pathway and found that the protein expression of TLR4, p-IKKα/β, IKKα, IKKβ, and p-IkBα was significantly increased in the lung tissues of the mice in the model group (P < 0.05) and that NAR was able to reduce the protein expression of TLR4, p-IKKα/β, IKKα, IKKβ, and p-IkBα (Fig. 3A).